If he has a an electric fuel pump then he could over the PSI required, if it is a stock style then the pump is faulty. They should be 6-7 psi. But with what the techs have been telling him I would double check the fuel pressure. And these carb have NO anti dieseling feature unless the carb is fitted with a kicker solenoid. The throttle plates do not move when the engine starts. The choke does but not the throttle plates.

 

I wouldn't assume an '81 would have an electric pump. If he has a throttle positioner, then the throttle plates are normally closed and only opened when the key is on/ in start. If any part of this system is not aligned properly, it would be a bitch to start.

 

When you are rebuilding the carb, look for dirt and rust flakes in the bottom of the carb. The most common cause for the carb to overflow is dirty fuel, usually caused by a rusty tank. The tanks in these trucks like to rust out at the top where they lay against the crossmembers.

 

Not all throttle kickers were electric there were vacuum ones, ya need engine vacuum for those to work. Usually an elec kickers would not not have enough pull to overcome the throttle return springs and open the throttle on it;s own, but would hold it open once the plunger bottoms out and the magnet force is strong enough to hold the plunger in position.
Not all applications had kickers either, AC equipped vehicles usually did to kick the engine idle up when the AC is on. And when you depress the pedal the throttle give it a shot gas on a cold motor the throttle would be sitting on the chokes high idle cam. But checking that the kicker is adjusted properly is still good idea. If it being used as an anti dieseling solenoid when it is disconnected the engine should stall.

And with these truck being 30 plus years old many have been been fitted with aftermarket electric fuel pumps as people think they are more reliable than the old mech pump. And they do have advantages as they will fill the carb's float bowl without the engine running so if you are boiling the carb dry on shut down, the electric pump avoids extended engine cranking during start..

As for a reasonable cost fuel pressure regulator
https://www.summitracing.com/int/par...9710/overview/

These little guys have been around for decades (since the 70's). It was originally a Purolator product (I still have a couple NORS U.S made Purolator ones kicking around) I guess they sold the design off to whoever and are prob built in china now. But any ways they always worked well and are super easy to adjust, just twist the ****. I used them as I have had a few Pierburg carb applications in the past that called for really low fuel pressures , like 2 psi low and many of of the fuel pumps used both mech and elec would just put out to much pressure for the poor old Pierburg.

 

 

So gas is pouring out the bowl vent after the cleaning?
If so the fuel in let valve (needle & seat) are not closing.
Could be junk between the 2
or
Put together wrong and they don't line up right .
or
Not adjusted right.
or
The float went belly up and sunk to the bottom of the bowl.
Dave ----

 

Dave, no, after the cleaning I have no more gas pouring out of the bowl vent. The throttle is responding better than ever and it hauls way more *** than before. Only thing now is the clunk/jerk from going from park to reverse and drive is pretty bad.

 

Your idle speed is too high.

 

Idle speed too high (should set to specs on emissions tag underwood) and maybe U-joints are worn.

 

 

With a multimeter, like this one:



https://shop.advanceautoparts.com/p/...7677/9020009-P

 

Thank you, looking over the user manual - and this will be extremely easy and has so many features to test all my other electrical gremlins.

 

One more issue: Every time I fill up, its very difficult to start. I only have use of my rear tank at the moment until I either coat the front one or replace it. After I fill up I have to wait 5-10 min after fill up to start or I've had success by just cranking it over and over. It doesn't matter if I fill it half way or full, always the same story. Any thoughts?

 

How long has the motor been running, 10-15 minutes to get to the station or hours like on a trip?
Have you tried holding the gas to the floor?
Dave - - - -

 

If your idle speed is too high and you can't get it lower, cut it off in gear, then put it in park. That'll keep rpms lower.